Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display device and a method of manufacturing the same, and more particularly, to a thin film transistor array substrate of an OLED display device and method of manufacturing the same.
Description of the Related Art
With the development of an information-oriented society, a demand for a display device for displaying an image has increased in various forms, and in recent years, various flat display devices such as a liquid crystal display device (LCD), a plasma display panel device (PDP), and an organic light emitting diode (OLED) display device have been used.
Among these display devices, OLED display devices use a self light emitting element, in other words a self-luminous element, and as a result, a backlight, which is used in an LCD device, is typically not required. Thus, OLED display devices can be lightweight and can have thin profile. Further, OLED display devices have wider view angle and higher contrast ratio than LCD devices and are also advantageous in power consumption. In addition, since OLED display devices can be driven with a direct current at a low voltage and have a high response speed and solid internal components, OLED display devices are resistant to external shocks and have a broader usable temperature range and have low manufacturing costs.
OLED display devices may display an image using a top emission scheme or a bottom emission scheme according to the structure of an organic light emitting element including a first electrode, a second electrode, and an organic emission layer. In the bottom emission scheme, visible light generated from the organic emission layer is displayed at the bottom of a substrate on which a TFT array is formed or located, while in the top emission scheme, visible light generated from the organic emission layer is displayed at the top of the substrate on which a TFT array is formed or located.
An OLED display device often includes a circular polarizing plate to implement a black of the OLED display device. In other words, an OLED display device may include a circular polarizing plate to improve the appearance of black and to reduce an amount of reflection by external light, thereby to improve the user's visibility. However, when an OLED display device uses a circular polarizing plate, its transmittance may be reduced, and as a result, its panel efficiency may deteriorate and its power consumption may increase.
In order to address these problems, an OLED display device may include a color filter disposed in a white sub-pixel area to reduce an amount of reflection by external light, instead of using a circular polarizing plate. In such a case, the light emitted from the organic light emitting element may be, however, absorbed in the color filter, and as a result, its light efficiency may deteriorate and its power consumption may increase.